1. Technical Field
The present invention relates in general to improved networking and in particular to a method for accessing data processing systems behind a NAT enabled network. Still more particularly, the present invention relates to receiving a source routing address with a DNS query response, such that loose source routing is enabled for accessing data processing systems behind a NAT enabled network from a client system located outside said NAT enabled network.
2. Description of the Related Art
The development of computerized information resources, such as interconnection of computer networks, allows users of data processing systems to link with servers within a network to access vast amounts of electronic information. Multiple types of computer networks have been developed that provide different types of security and access and operate at different speeds. For example, the internet, also referred to as an “internetwork”, is a set of computer networks, possibly dissimilar, joined together by means of gateways that handle data transfer and the conversion of messages from the sending network to the protocols used by the receiving network. When capitalized, the term “Internet” refers to the collection of networks and gateways that use the TCP/IP suite of protocols.
For a computer to communicate with other computers and servers on the Internet, it must have an Internet Protocol (IP) address identifying the location of the computer on the network. Thus, an issue facing the Internet is the depletion of address and scaling in routing that arises with the increase in home and business networks.
Many computers are arranged in a local area network (LAN) or wide area network (WAN) that is a private network used by an individual or business. Computers operating within the private network often have access to the Internet. Thus, an issue facing many individuals and businesses is how to protect data within a local network of computer systems that also have access to the Internet.
Both the addressing and security problems are often solved using a Network Address Translation (NAT) enabled router with a firewall. When NAT is implemented, the individual machines within a private network have unique private addresses rather than unique public IP address. Thus, a single IP address is used by the NAT router and a port mapping scheme is implemented to route packets to data processing systems in the NAT network. As a result, it is simple for a data processing system in the NAT network to contact an outside system via the Internet because all communications take place using the NAT router's IP address. Adding additional security, communications routed to the Internet hide the unique local address of the data processing system in the NAT network. Additionally, a port mapping scheme of the NAT router is implanted to route received packets to specific data processing systems in the NAT network.
While NAT provides solutions to the addressing and protection problems, there are also several disadvantages to NAT. Primarily, while it is easy for machines within the NAT network to contact machines outside the NAT network, the reverse is not true. A user at work may want to access his home machine to download images from the home machine or telnet to the home machine, for example. Current NAT techniques do not allow such access directly to machines within the NAT network. Therefore, it would be advantageous to provide a method, system, and program for accessing data processing systems behind a NAT enabled network. Further, it would be advantageous to provide a method, system, and program for accessing data processing systems behind a NAT enabled network without requiring use of a dedicated port.